Set default pool when RBE or goma is enabled

Pass --default_pool=local_pool to kati when RBE or goma is enabled
to put most rules into the local_pool.  Specific rules that support
RBE or goma will set .KATI_NINJA_POOL := none to remove themselves
from the local_pool.  Passing --default_pool will also disable the
hack in kati that sets the pool based on the presence of the string
"/gomacc" in the command line.

Fixes: 143938974
Test: inspect pools in build-${TARGET-PRODUCT}.ninja for m USE_RBE=true
Test: inspect pools in build-${TARGET-PRODUCT}.ninja for m USE_GOMA=true
Change-Id: I839b2488383fcd63fffd613e25b0b9abcb72b567
diff --git a/ui/build/config.go b/ui/build/config.go
index 92aee4d..c8670ae 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -767,6 +767,10 @@
 	return true
 }
 
+func (c *configImpl) UseRemoteBuild() bool {
+	return c.UseGoma() || c.UseRBE()
+}
+
 // RemoteParallel controls how many remote jobs (i.e., commands which contain
 // gomacc) are run in parallel.  Note the parallelism of all other jobs is
 // still limited by Parallel()